Esters of polymers of maleic anhydride and beta-mercaptoethanol and process



Patented Sept. 9, 1 952 Milton Kosmin and John Mann Butler, Dayton, Ohio, assignors to Monsanto Chemical Company, St. Louis, Mo., a corporationoi' Delaware No Drawing. Application June 24, 1949,

i Serial No. 101,248r

p 10 Claims. (01. 260-481) This invention relates to a new family of L O g n chemical compositions and to their use as pour "H i H r Y point depressants for lubricating oils. More Q E* specifically the invention relates to esters of the H H V 1) reaction product of maleic anhydride and {3- .m mercaptoethanol. i b Many of the commercially available petroleum stocks contain high molecular weight hydrocarbon waxes, and the lubricating fraction separated by various refining procedures contain a r V tr substantial proportion oi the waxes dissolved therein. Upon cooling these lubricants, the dis- BO'C2H* S fi solved waxes crystallize in such form that the i Q fluidity of the lubricant is destroyed. It is known that some substances effect the crystal- It W111 be notlced that the compounds repre" lization of the wax andpermit the lubricants Snied by the strutftuml tormtflae may condense to retain their fluidity after cooling below the Wlth each other W form alkyd normal pour points of the oils; polymers. Polymers of these types appear to be The purpose of this invention is to provide a 0 present, m the mtermedlate compound? .1 new class of compounds having, unusual utility i0 proportions of the polymers and the addition as an additive for lubricating oils. A further pmducts represented by i a (2) purpose of this invention is to provide an effec- (3) depend :P the mql proportlons tive means of reducing the pour points of wax of malelc anhydnd? and fl'mercaptoethanol containing lubricating oils. ,l charged to the ft The pour points of lubricating oils are The Pondensatlon. male: i q t with measured by a standard A. S. T. M. procedure, fiimfarcaptoethanol 71S ptefembly mmated by by which a sample of oil is heated and then mlxmgthe reagents s li t t gradually cooled while observing the fluid charexample. from to h reactlon acteristics of the sample at every 5 F. interval, 1: exothermlc' so the rtactlon m e t be the temperature being multiples, of 0 R The 30 teated. After the initial reaction has subsided pour point is the lowest recorded temperature reactwn mass may be m to hlgtjer at which the Sample is fluid. The details of pemtmfes' example fromtfo to 100 AS the method of determining pour points are set a react-1on1 progeeds the reactwn mass becomes forth in the American Society for Testing Ma- $f ig f i d m g for terials Bulletin; on petroleum products and luthe desired gg fi g f f s? upon bticants 13-97-39. t t t In general low molecul i veigtit pr dfi t a i e t h r comporifeifit35it"itiltifi miiifitffittfii 5535x5833 Ziitfiitii"fioiggfipt ti g ig 3? with fi-mercaptoethanol andthereafter esterifynumber. of maleic acid units molecul: i? m the product Withia normal primary alcohol polymer will usually be between two and three containing from twelve to eighteen carbon atoms, The polymers of maleic anhydride and Emmet; 3 11 3 1 33 (gfia rififfi zogfgggi g aig gg earea captoethanol are then reacted with normal priby reacting maleic anhydride and fl-mercfihtotar etti g t fii fi xt t 'ti t 12 1 V 1 ure 0 sa1 acoos. ittitt pitttci ielltif ii iiitfiiit fitti ticitfii if fi iat' i i if? if l i ,-e ecy acoo,ormixures e 3 3 3225 2;fiz gg zg sg of two or more of said alcohols or mixtures of f d V y 7 y alcohols containing a substantial portion oi an i esired. wlth s ll p oportion of a free adalcohol. havlng from twelve to eighteen carbon cal producing catalyst, for example a peroxide atoms in the molecule. The low molecular such as ascaridole or benzoyl peroxide. The weight maleic anhydridepolymer is esterified by chemical COIIStItHtIOD of the polymeric intermixing the alcohol and the polymer in the presmediate has not definitely been ascertained. ence of a suitable hydrocarbon diluent, preferlt-is, however, believedto be a mixture. of comably'a solvent for the reactants and, if desired pounds including some or all of the following:

an esterification catalyst. The mixture is then refluxed until the theoretical quantity of water is evolved by esterification and recovered by a suitable trap in the condenser. Sufiicient alcohol should be used to react with all available carboxylic acid radicals.

. From. 0.01 to five percent by weight of the new chemical compounds are useful in depressing pour points of oil but preferred practice involves the use of from 0.05 to two percent. The polymer is dissolved or dispersed in the lubricating oil by dissolving it directly and stirring it until a homogeneous mixture or solution is eifected. It is frequently desirable to prepare master batches by dispersing or dissolving large amounts of the new compounds in a lubricatin'g stock and thereafter mixing the concentrate with a suitable larger quantity of untreated oils, the

dodecanol, 21 percent tetradecanol, 11 percent hexadecanol, and 2.2 percent octadecanol, was used for the esterification. The mixture was refiuxed until three ml. of water had been evolved and separated During the latter portion of the reaction two small crystals of toluenesulfonic acid weradded to catalyze the reaction. The product was worked up in the manner described in the preceding examples.

The utilityfof the compounds described in the precedingthree examples was demonstrated by preparingione percent solutions of each in several differentlubricating oils having pour points of F., 20 F.--,- 45 F., and 60 F., in each case.

The pour points of the modified oils were measproportions being chosen so as to achieve small but effective proportions of the new compound in the final lubricant.

The new compounds of this invention may be used alone or in combination with other known pour point depressants, and with other modifying agents, such as antioxidants and detergents.

Further details with respect to the preparation of the new compositions of matter are set forth with respect to the following examples.

Example 1 Examplez A glass reaction flask was provided with a reflux condenser and a Dean and Stark trap for separation of water from the condensate. The flask was charged with 37.2 grams of a straight chain alcohol having twelve carbon atoms, 17.6 grams of the compounds prepared in accordance with Example 1, and 17 ml. of toluene. The flask and its contents were heated-at reflux temperature until two ml. of water had been separated. The reaction mixture was then diluted with benzene, washed well with water and with sodium bicarbonate. After drying the solventwas evaporated.

- Example 3 A glass reaction vessel, provided with a reflux condenser and a Dean and Stark trap for the separation of evolved water was charged with 44 grams of the polymer prepared in accordance with Example 1, 107 grams of n-tetradecanol and 50 m1. of toluene. The mixture was heated at the reflux temperature until ml. of water had been removed. The product was diluted with an equal volume of benzene and washed with water and finally with sodium bicarbonate. After the solution was dried, the solvent was evaporated. A viscous liquid product was thereby obtained which solidified 'upon standing. The product was identified asthen-tetradecanol ester of the. polymer prepared in accordance with Example ;l.' V

" Emample 4 Using the procedure of the preceding examples, except that 40 grams of a mixture of alcohols consisting of 2.8 percent decanol, 61 percent ure d by the standard A. S. T. M. procedure and the following observations were made:

Lubricating oils having original pour of Compound of A .The above: tabulationdemonstrates that the derivatives of tetradecyl alcohol is an effective depressant for 45F. pour oil, causing a reduction of 20 in the pour point. Similarly, the derivatives of, dodecyl alcohol is an effective pour point depressant for 0 F. pour oil but not for other oils. The table also demonstrates that the derivatives made from a mixture of C8 to Cu; alcohols is an effective pour point depressant for 20 pour oil, but is not effective on either 0 F. pour oil or 45 F- pour oil.

The invention is described following claims. I

1. A composition of matter made by the esterification of polymers of maleic anhydride and fl-mercaptoethanol with primary normal alcohols having from twelve to eighteen carbon atoms, said polymers containing an average of at least two maleic anhydride units per molecule.

2. Asa. composition of matter the ester of a normal aliphatic alcohol havingfrom twelve to eighteen carbon atoms with a polymer made by reacting from one to two mols of maleic anhydride with from two to one mol of ,B-mercaptoethanol, said polymer having anaverage of at leasttwo maleic anhydride units per molecule.

3. As acomposition of matter the dodecanol ester of a low molecular weight polymer made by reacting equal mols of maleic anhydride and 5- mercaptoe'thanol, said polymer having an average of at least two maleic anhydride 'units per molecule.

4. As a composition of matter the .tetradecan01 ester of a 'low molecular weight polymer made by reacting equal mols of maleic anhydride and l3-mercaptoethanol, said polymer having an average of at least two maleic anhydride units per molecule 5. As a compositionof matter mixtures of esters of aliphatic alcohols having from twelve to eighteen carbon atomsin the molecule and a lowmol'ecular weight polymer prepared by reacting equal mols of maleic anhydride and B- mercaptoethanohsaidpolymer having an averageof atleast'two maleic anhydride units per molecule. v

o A -method of preparing an 'oil additive with respect to the which comprises reacting maleic anhydride and p-mercaptoethanol to form a polymer containing an average of at least two maleic anhydride units per molecule, and thereafter esterifying the said polymer with a primary alcohol having from twelve to eighteen carbon atoms.

7. A method of preparing an oil additive which comprises reacting from two to one mol of maleic anhydride and from one to two mols of ,B-mercaptoethanol to form a polymer containing an average of at least two maleic anhydride units per molecule, and thereafter esterifying the said polymer with a primary normal alcohol having from twelve to eighteen carbon atoms.

8. A method of preparing an oil additive which comprises reacting equal mols of maleic anhydride and fi-mercaptoethanol to form a polymer containing an average of at least two maleic anhydride units per molecule, and thereafter esterifying the said polymer with n-dodecanol.

9. A method of preparing an oil additive which comprises reacting equal mols of maleic anhy- 6 dride and fi-mercaptoethanol to form a polymer containing an average of at least two maleic anhydride units per molecule and thereafter esterifying the said polymer with n-tetradecanol.

10. A method of preparing an oil additive which comprises reacting equal mols of maleic anhydride and B-mercaptoethanol to form a polymer containing an average of at least two maleic anhydride units per molecule, and thereafter esterifying the said polymer with a mixture of primary normal alcohols having from twelve to eighteen carbon atoms.

MILTON KOSMIN. JOHN MANN BUTLER.

REFERENCES CITED UNITED STATES PATENTS Name Date Blake July 26, 1949 Number 

1. A COMPOSITION OF MATTER MADE BY THE ESTERIFICATION OF POLYLMERS OF MALEIC ANHYDRIDE AND B-MERCAPTOETHANOL WITH PRIMARY NORMAL ALCOHOLS HAVING FROM TWELVE TO EIGHTEEN CARBON ATOMSL SAID POLYMERS CONTAINING AN AVERAGE OF AT LEAST TWO MALEIC ANHYDRIDE UNITS PER MOLECULE. 